What are the men in this photo wearing?
The men in the picture are wearing modernized versions of zoot suits.
A zoot suit is a men's suit with high-waisted, wide-legged, tight-cuffed, pegged trousers, and a long coat with wide lapels and wide padded shoulders.
The members of the African-American, Chicano, Filipino American, and Italian American communities became the first zoot suiters of the 1940s. A lot of jazz musicians used to appear in zoot suits onstage, which made this style of clothing popular among different social groups. As an original outfit, a zoot suit became an inspiration for many other fashionable costumes. For example, the British "Edwardian-look" suits with velvet lapels worn by Teddy Boys is said to be a derivative of the zoot suit.